Currently, many articles of manufacture such as dosage forms for delivering a drug involve a process of membrane coating to a core of drug, where an organic solvent, for example, acetone and/or methylene chloride is used for applying the membrane. Unfortunately, there are serious limitations with organic solvent coating processes. That is, the organic solvents are expensive, they are explosive, and they can cause environmental concerns. Moreover, organic solvent coating with a mixed solvent system is accompanied by inherent different evaporation rates of the solvent components, that makes it difficult to form uniform membranes. Then, it becomes time-consuming and costly to optimize coating conditions for scale up. These prior art processes might give rise to a lack of uniform membranes and these variances in membrane morphology often subtract from producing quality articles of manufacture.
In the U.S. Pat. No. 5,614,578, patentees Dong, Wong, Pollock, and Ferrari made available to the injection-molding and membrane arts inventive compositions for forming injection-moldable membrane comprising poly(caprolactone), poly(alkylene oxide), and poly(ethylene glycol). These compositions are successful for manufacturing articles of commerce such as dosage forms by injection-molding using a cold-runner mold. However, in hot-runner mold operations, serious technical problems are encountered as the compositions exhibits phase-separation into its components leading to poor mechanical properties and reduction of manufacturing speed.
It will be appreciated by those skilled in the injection-molding art that a critical need exists for a novel polymeric composition for injection-molding that is free from the problems associated with the prior art. Likewise, it will be appreciated by those skilled in the art, that if a novel composition is provided for injection-molding a membrane for manufacturing a dosage form, such a composition would represent a positive advancement and an unexpected improvement in both the polymer and dosage form arts.